The present invention relates to a fastener, and in particular to a screw type threaded fastener used in securing two items together, such as a floor board to a truck body, or other similar application.
In certain environments, for example in the application of a wood or plastic material wall to metal channels, frames or plates in the interior of a semi-trailer truck body, threaded fasteners are used which need to address many different problems.
The threaded fastener should have some means for remaining secured to the metal frame so that the fastener will not come loose in the high vibration environment in which it is used.
Also, it is desirable for the fastener to thread quickly into the materials to be fastened together.
One fastener that addresses some of these problems is disclosed in U.S. Pat. No. 5,964,560, assigned to the assignee of the present application. That patent discloses a threaded fastener in which a shank of the screw has a first trilobular thread area which rolls threads rather than cutting threads for a tighter fit. The thread has flats provided at the tip and three threads formed on the shank have beginnings at the tapping point, with one lead starting at each lobe. The screw has 18 threads per inch when the shank has a diameter of 5/16 inches and 20 threads per inch when the shank has a diameter of ¼ inches, thus resulting in a thread angle (when viewed from the side of the fastener) of about 11 degrees to provide a thread which will cause the fastener to be drawn into the material quickly, however, not so fast as to prevent the fastener from being able to cut into metal and to pull itself into the metal. The threads continue along the shank from the tip, but stop short of the head at an unthreaded portion of the shank.